Cloud Attenuation in Millimeter Wave and Microwave Frequencies for Satellite Applications over Equatorial Climate
- PDF / 150,764 Bytes
- 6 Pages / 439.37 x 666.142 pts Page_size
- 102 Downloads / 184 Views
Cloud Attenuation in Millimeter Wave and Microwave Frequencies for Satellite Applications over Equatorial Climate J. S. Mandeep & S. I. S. Hassan
Received: 29 October 2007 / Accepted: 19 November 2007 / Published online: 27 December 2007 # Springer Science + Business Media, LLC 2007
Abstract A propagation experiment has been carried out at Penang using the SUPERBIRD-C satellite beacon. Cloud occurrences were observed during different months and it is seen that the low cloud occurrences over Penang is very significant from October to January. The cloud attenuation results that are presented, which include the testing of models, have been obtained from the data gathered over five years. The specific attenuation of radio wave due to clouds at various frequencies 12 GHz, 20 GHz, 75 GHz, 50 GHz and 100 GHz has been estimated whereby the values varies from 0.14 dB/km at 12 GHz to 10.1 dB/km at 100 GHz. Keywords Cloud attenuation . Millimeter wave . Equatorial climate
1 Introduction Tropospheric propagation impairments that affect satellite communication signals increase in severity with the increase of frequency. Precipitation effects are the main impairment factor for millimeter wave signals propagating through the atmosphere. However, many projected Ka-band and V-band services uses small terminals and, for these, rain effects may only form a relatively small part of the total propagation link margin. But cloud attenuation, that may cause deep fades in these band, is one of the components that need to be considered for low availability satellite links owing to its higher probability of occurrence [1, 2]. A number of experimental studies of atmospheric attenuation at millimeter wave have been conducted. Based on the studies, researchers with some confidence can estimate the losses due to gaseous absorption and rain throughout the millimeter wavelength spectrum. However it is difficult to estimate the losses due to clouds since only limited experimental data are available [3]. J. S. Mandeep (*) : S. I. S. Hassan School of Electrical and Electronic Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Seberang Perai Selatan, Pulau Pinang, Malaysia e-mail: [email protected]
202
Int J Infrared Milli Waves (2008) 29:201–206
In this paper, five years results for cloud attenuation, including comparison of experimental distributions with model predictions are presented and discussed. An attempt has been made to provide the statistics of cloud occurrences for low cloud types and total (all cloud types included). The specific attenuation of radiowave due to clouds at various frequencies 20 GHz, 50 GHz and 100 GHz has been calculated.
2 Experimental system configuration The receiving station includes a 2.4 m antenna to collect horizontal signal polarization at 12.255 GHz by means of a digital beacon receiver. The diameter of the antenna was set at 2.4 m as a compromise to have large fade margin (20 dB), and a not-too-narrow antenna bandwidth (0.5°), so that a tracking system was not necessary. A
Data Loading...
